A Domain Name is a sign post to a website. For example the domain name www eirspace.com equates to a number, 216.248.192.108. This series of numbers points to the eirspace website.

The www is a standard part of the address. You get to choose the centre section, however some restrictions apply. Below are the rules for .com, .net and .org:

		Use only letters, numbers or hyphen(“-”)
		Cannot begin or end with a hyphen
		Cannot exceed 67 characters in total
		Domain names are not case sensitive
		Domain names cannot include spaces

In the case of the .ie domain it becomes somewhat more complicated:

		The .ie name must be derived from the name of the applicant
		For each name used, the applicant only gets one domain, except in the case of bodies corporate, which can register multiple domain names to reflect their corporate names.
		You can't register a domain based on someone else's name.
		The name has to be between three and 63 characters long, consisting of only the letters 'a' to 'z', the digits '0' to '9' and a hyphen ('-').
		The names of Irish places are only registered to the relevant local authorities.
		Generic names will not be registered, subject to some exceptions.

For more information check out www.domainregistry.ie